Control means for driving and tensioning ink ribbons to high speed printing machinesd



Dec. 13, 1966 M. A. R. BERNARD 3, 9

CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES Filed March 1, 1965 8 Sheets-Sheet 1 a 4%TL 5) mm A ih M/L Dec. 13, 1966 M. A. R. BERNARD 3,291,043

CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES Filed March 1, 1965 8 Sheets-Sheet 2 Dec. 13, 1966 M. A. R. BERNARD CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES 8 Sheets-Sheet 8 Filed March 1, 1965 mmz m'ywm .2) a IQW Dec. 13, 1966 M. A. R. BERNARD CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES 8 Sheets-Sheet 4 Filed March 1, 1965 Dec. 13, 1966 M A. R. BERNARD 3, ,0 3

CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES Filed March 1, 1965 8 SheetsSheet 5 MM.- mmzm zfm; 6m 3) 5mm 4* %AW Dec. 13, 1966 M A. R BERNARD 3,291,043

CONTROL MEANS FOR bRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES Filed March 1, 1965 8 Sheets-Sheet 6 Dec. 13, 1966 M A. R. BERNARD 3,291,043

CONTROL MEANS FOR I JRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES Filed March 1, 1965 8 Sheets-Sheet 7 (10/ C102 |CI04 C103 Dec. 13, 1966 M. A. R. BERNARD CONTROL MEANS FOR DRIVING AND TENSIONING INK RIBBONS TO HIGH SPEED PRINTING MACHINES 8 Sheets-Sheet 8 Filed March 1, 1965 CH0; CH06 777% M mzmmaL United States Fatent Gfifice Mamet Patented Dec. 13, 1966 3,291,043 CUNTROL MEAN FOR DRIVENG AND TENSION- ING llNK RIBBONS TO HIGH SPEED PRINTING MACHINES Michel Andi- Robert Bernard, Asnieres, France, assignor to Societe llndustriclie Bull-General Electric (Societe Anonyme), Paris, France Filed Mar. 1, 1965, Ser. No. 436,108 Claims priority, application France, Mar. 19, 1964,

3 Claims. (ct. 101-96) The present invention relates to improvements in arrangements concerning the printing ribbon in printing machines comprising an inked ribbon for the printing of marks, signs or characters by mechanical striking, as also to improvements applicable more particularly to highspeed printing machines for recording data, in mechanographical accounting units and in electronic equipment for the rapid processing of information.

The invention will be described in its application to arrangements concerning the inked ribbon employed for printing in a drum-type printing machine for printing data, line-by-line, on one or more paper tapes advanced step-by-step in the said machine past a row of printing mechanisms. Machines of this category can normally operate at printing speeds of 50,000 to 100,000 characters or signs per minute, depending upon the speed of rotation of the character drum and are particularly adapted for high-speed printing of bank accounts, tables of calculation results, pay-slips, invoices, statements, etc. Having regard to the importance generally attached to data thus printed, these machines must ensure with regularity high printing quality which guarantees complete legibility of the printed characters or signs. Having regard also to the considerable quantity of documents thus produced, it is also necessary to obtain a minimum printing cost. All these conditions are completely satisfied with welldesigned drum-type printing machines provided with the improvements according to the present invention. However, it will be obvious to any person skilled in this field that the improvements according to the present invention are also adaptable to printing machines in which the characters are mounted on wheels or toothed racks, as also to a large variety of recording machines comprising an inked ribbon or the like wich is employed for printing.

It is known that, in printing machines, typewriters and like machines comprising an inked ribbon, the same ribbon usually serves for economically producing a large number of impressions of high quality in the course of a number of passages through the machine since, to some extent, the ink remaining in the ribbon is redistributed in the said ribbon by capillarity after each run.

The invention also concerns arrangements which have the object of facilitating the rapid positioning and tensioning of the ribbon in a printing machine or the extraction of this ribbon without the operator having to soil his or her hands in the course of this operation. Particular arrangements are provided for automatically ensuring a constant and sufficient tension of the ribbon in order to maintain the latter in a precise position in relation to the paper and in relation to the character drum in the printing mechanism, so as to prevent any excessive transfer of ink from the ribbon on to the drum and to reduce soiling of the paper by rubbing of the ribbon thereon.

Further advantages and features of the invention will become more clearly apparent in the course of the fol lowing description, with reference to the accompanying drawings, in which:

FIGURE 1 is an external view of a high-speed drumtype printing machine provided with the improvements according to the invention;

FIGURE 2 is a diagrammatic view in perspective indicating the relative positions of the inked ribbon, of the character drum and of various parts in the machine;

FIGURE 3 is a diagrammatic view in section along the line 33 of FIGURE 5 of the ribbon-drum mechanism, shown in the open position with an inked ribbon in position;

FIGURE 4 is a view in section along the line 44 of FIGURE 6 showing the parts for the manual control of the supporting winders for the inked ribbon;

FIGURE 5 is a fragmentary view along the line 55 of FIGURE 3 through various members in the left-hand art of the ribbon-drum mechanism;

FIGURE 6 is a fragmentary view along the line 6-6 of FIGURE 4 through various members of the right-hand part of the ribbon-drum mechanism;

FIGURE 7 is a part of the diagram of the electric circuits for monitoring and controlling the movements of the inked ribbon, and

FIGURE 8 is another part of the diagram of the circuits for monitoring and controlling the ribbon.

The machine of which FIGURE 1 is an external view is a high-speed printing machine comprising a character drum, of which the main elements are assembled in one cabinet comprising a number of parts. A pedestal S supporting the whole machine is provided with a platform P which supports suitable means for supplying the machine with paper (paper in roll form or folded in zig-zag vform). The said pedestal S comprises, at the rear of the machine, known devices (not shown) arranged to receive the paper after it has entered the machine. A part F resting on the pedestal S and secured to the latter contains mainly the striking mechanisms and electric circuits for controlling or monitoring the actuation of the hammers of the said mechanisms for the printing. At the front of the part F of the machine is disposed a part BT called the ribbon-drum block which contains the character drum, the inked ribbon and the electromechanical members for the control and drive of the character drum and of the ribbon. The block ET is adapted to rock about a horizontal axis fast with the part F, in order to permit ready access to the devices contained in the said block. A compensating mechanism, which is known in the art and not described, balances the block BT and enables the latter to be brought from the closed position to the open position, or vice versa, gently and without shocks, having regard to the thrust applied by the striking mechanisms during the operation of the machine. An assembly AP disposed above the part F of the machine comprises all the electromechanical means for automatically effecting the step-by-step advance and the return movement of the paper in the machine. The part AP of the machine comprises in its left-hand part (FIGURE 1) three control push buttons. The upper buttons TS is provided for manually monitoring the electric control of the traction members of an upper paper drive mechanism. A button TI situated below the first button serves to control the traction members of a second paper advance device independent of the first. A button CM serves to control the motors for stopping the machine.

A block ME secured to the right of the machine and provided with movable panels contains the control circuits and the electronic devices necessary for establishing the connections between the printing machine and the computing equipment, the reading devices or the like which are connected thereto and transmit thereto control indications or data to be printed. Various electric circuits and more particularly relay circuits for controlling or monitoring the movements of the ribbon in the machine (and which will hereinafter be described) are disposed mainly in the part S and are accessible from the side through a hinged casing.

The ET is shown in solid lines in FIGURE 1 in its normal position, i.e. in the closed position which it necessarily occupies during the printing of data, but the same figure also shows, in dash-dotted lines, the block BT which is illustrated in the open position. This position corresponds to the position in which the drum unit is diagrammatcally illustrated in secton in FIGURE 3. Owing to the fact that the invention relates mainly to means concerning the printing ribbon and its control devices, only the means and electric circuit diagrams relating thereto will be described. However, the printing mechanisms and the mechanisms for the advance of the paper which are associated with the printing ribbon will not be described in detail, but are partly shown in FIG- URES 4 and 5, which are fragmentary sectional views through the machine at the level of the printing mechanisms. The paper 139 which arrives (FIGURE 1) from the bottom of the machine, passes between the part F of the machine and the block BT, which are provided (FIGURES 3 and 4) with plates 182, 183, 184 and 185 for guiding the said paper between the character drum 102 and the striking mechanism 114. The paper thereafter asses over a roller 115 and is then driven by means of marginal perforations by toothed-chain traction devices 116 of known type (FIGURES 1 and 4).

The diagrammatic drawing of FIGURE 2 shows in perspective the relative position of the main parts associated with the character drum and the inked ribbon in the block BT. The same parts are shown in FIGURE 3 to 6. The ribbon 101 is secured at its ends to two supporting rollers 103 and 104 through flexible bands 105 and 106, which are wider than the ribbon and are each provided with a bar 108 and a bar 109 respectively. These bars are adapted to act on electric contacts C11 and CIS (FIGURES 2, 3, 5 and 7) for monitoring the reversal of the movement of the ribbon when one end of the latter advances towards the printing line 107, on which the striking mechanisms are aligned in the machine. Contacts CIS and 011 may be provided, as shown in FIGURE 2, on either side of the ribbon and connected in parallel for greater reliability of operation. Close to the upper supporting roller 103, the inked ribbon 101 passes (FIG- URES 2 to 6) over a roller 112 arranged to detect the effective advance of the ribbon. This roller, which is arranged to turn freely about its axis, is rotated by the friction of the ribbon in one direction or the other, depending upon the direction of travel of the said ribbon. A earn 113 connected to the roller 112 is provided (FIG- URE 2) with bosses arranged temporarily to close a contact CAR (FIGURES '2 and 7) in order to detect the effective advance of the ribbon in response to the transmission of a signal for the movement of the latter. This cam-operated contact device is contained in a casing 111 (FIGURES 3, 4 and 5). The inked ribbon 101 is guided (FIGURES 2 and 3) past the printing line 107 by means of two rollers 117 and 118 which maintain the said ribbon in immediate proximity to the character drum 102 without, however, touching it. A guide roller 119 disposed below the drum guides the ribon close to the lower supporting roller 104. The mechanisms associated with the character drum and with the inked ribbon are mounted (FIGURES 3 to 6) in the block BT, on a supporting frame 140 which is adapted to pivot about a horizontal shaft 141 mounted on two bearings 142 and 143 (FIGURES 5 and 6 respectively) connected to the frame of the part F of the machine. The supporting frame 140 is provided with a left-hand cheek 144 (FIGURES 3 and 5) and with a right-hand cheek 145 (FIGURES 4 and 6) which support all the mechanisms of the block BT.

The ribbon-supporting roller 103, in the upper part of the mechanism, is engaged between two winders, i.e. an upper driving winder 150 (FIGURES 3 and 5) and an upper supporting winder 152 (FIGURE 6), while the ribbon-supporting roller 104, which is in the lower part of the mechanism, is engaged between a lower driving 4 winder 151 (FIGURES 3 and 5) and a lower supporting winder 153 (FIGURE 6). The driving winders 150 and 151 are each mounted (FIGURE 5), by way of ball bearings, in supporting members 154 and 155 let into the lefthand cheek 144. The upper driving winder 150 is coupled to a motor MRS (FIGURES 5 and 8) and the lower driving winder 151 is coupled to a motor MRI, through reduction gears RS and RI respectively, which are reversible so that when a ribbon supporting roller is driven by one motor, the other motor can be driven by the other supporting roller under the effect of the traction exerted on the ribbon by the driving motor. The motors MRS and MRI are single-phase induction motors of known type, the particular operating conditions of which will hereinafter be described and which are diagrammatically shown at MRS and MRI in the circuit diagram of FIGURE 8. The winders are each provided with a conical portion engageable in one end of a ribbon supporting roller, the said conical portion being formed with recesses 130, 131, 132 (FIGURE 3) to permit the engagement of one or two fingers of the hand of an operator in one end of a roller in order that one or both supporting rollers of a ribbon may be gripped by both hands. The conical portion of the driving winders 150 and 151 is in addition formed with striations 149 (FIGURE 3) which are designed to increase the necessary adhesion between the said driving winders and the ribbon supporting rollers. The conical portion of the winders 152 and 153 is connected (FIGURE 6) to a cylindrical body 121 mounted on ball bearings in order to enable the said winders to turn freely about a pin 122 provided with a bearing surface 123, which is arranged to slide in a bore in the guide member 124 secured to the cheek 145 of the supporting frame 140. A cylindrical portion 125, connected to the pin 122 and disposed in prolongation thereof, is arranged to slide in a guide 126. A spring 127 disposed between the bearing surface 123 and the guide 126 tends to push the conical bearing surface of each supporting winder to the left in order to centre and-maintain a ribbon supporting roller between the conical surface of one driving winder and the conical surface of the said supporting winder. The means associated with the lower winders are in principle identical to those of the upper winders except in regard to the members for the manual control of the supporting winders, which will hereinafter be specifically described. The cylindrical portion of each supporting winder is provided at its end with a dog 128 adapted to slide in a groove 129 in a bearing surface 136 on the guide member 124. A cylindrical sleeve is arranged to turn about the bearing surface 136 and is formed with a helical groove 133 in which the dog 128 is also engaged. A screw 137 held fast in the sleeve 135 is provided with a projection engaged in a circular groove in the bearing surface 136 of the guide member in order to maintain the said sleeve on the said bearing surface. The sleeve 136 of the upper supporting winder is in addition provided with a control lever 146 comprising a crank button 147 (FIG- URES 4 and 6). Another lever 148, fast with the sleeve 135, is coupled by a connecting rod 159 to a lever 158 identical to the lever 148 and connected to the sleeve 156, in order to control the lower supporting winder so that, by lowering the lever 146 (FIGURE 4) from the position A to the position B (in dash-dotted lines), the helical cam surface 133 provided on each sleeve (135156) and acting on the corresponding dog 128, displaces the conical portion of each supporting winder (FIGURE 6) to the right, in order to disengage the ribbon supporting rollers 103-104. The cam surface 133 on the operating sleeve of each of the supporting winders may be provided in known manner with a fiat or catch to maintain the supporting winders in the retracted position during the operations of positioning and extracting an inked ribbon. A manual action in the opposite direction on the control lever 146 of the sleeve 135 releases the supporting winders, which are automatically brought back into the locking position in the supporting rollers by the springs 127. A motor 160 for driving the character drum 102 is supported (FIGURE 6) by a plate 161 connected to the supporting frame 140. The shaft 162 of this motor is provided with a pinion 166 which meshes with a wheel 165 keyed on the shaft 110 of the character drum, which is supported by ball bearings mounted in the cheeks 144 and 145 of the supporting frame The plate 161 also supports a push button electric contact TR (FIGURES 6 and 7) for electrically effecting the advance and the tensioning of the inked ribbon, as will hereinafter be described. The cheeks 144 and 145 of the frame are provided, in their upper part, with adjustable stops 169 and 170 (FIGURES 3 to 6) by means of which the position of the character drum 102 may be exactly adjusted in relation to the striking mechanisms 114 (FIGURE 4) when the block ET is in the closed position (FIGURES 1 and 4) for the printing. The supporting members 124 and 154 of the upper winders are provided with extensions 172 (FIGURE 6) and 171 (FIGURES 3 and 5) respectively which are arranged to support a ribbon supporting roller in the upper position when the upper supporting winder is retracted. These extensions are so arranged as to maintain the roller in immediate proximity to its centering position on the winders, so that the roller is automatically lifted and centred on the conical bearing surfaces of the upper winders when the supporting winder 152 is advanced to the left (FIGURE 6) under the action of the spring 127, and when the latter is released by a manual action on the crank button 147 of the lever 146, as has been described.

The winders of the lower position are also each provided with means so arranged as to maintain a ribbon supporting roller in proximity to its centering position when the lower supporting winder is retracted. For this purpose, the supporting member of each lower winder is provided with a pin 173, on which there is rockably mounted a supporting lever 16% provided with arms 174 and 175 (FIGURE 3). The arm 175 of each supporting lever is secured to a plate 176 provided with stops 177 constantly bearing against the plate 183, which is disposed on the front face of the part F of the machine, under the action of a spring 179 acting on the arm 174 of the lever 168. The plate 176 has the object of maintaining the printing paper 139 against the part F of the machine and away from the inked ribbon, while various manipulations may be carried out on the said ribbon, or on other elements of the block ET. The arms 174 of the supporting levers 168 comprise a curved portion adapted to re ceive and support the ends of a ribbon-supporting roller in proximity to the centering position of the latter on the lower winders. For the positioning of a roller on the said lower winders, the lower supporting winder 153 having been removed, the said roller may first be deposited in a recess 178 in the arm 175 of the levers 16R.

'whereafter this roller can be pushed towards the arms 174. The rolling of the roller along the supporting levers has the effect of partly rewinding, or moderately tensioning, the ribbon. Since the latter is thus brought into position and approximately tensioned, the lever 146 controlling the upper supporting winders (FIGURE 4) is lifted, and the ribbon supporting rollers are then gripped by the winders and thus made fast with the driving winders.

For a rational use of the inked ribbon, it may be desirable for it to be automatically fed as a function of the printing operations performed by the machine. The electric circuit diagram of FIGURES 7 and 8 illustrates the principle of the circuits for controlling or monitoring the movements of the ribbon, and comprises manually operated, cam-operated and relay-operated contacts designed to be used under conditions which will be described. FIGURES 7 and 8 relate to the same electric circuit diagram, of which various parts may be considered independently of one another. In this diagram, the +48- volts, 48-volts direct-current supply is common to the diagrams of the two figures. The relay contacts are denoted by the same reference as the winding controlling them, but preceded by the letter C. A contact which is normally closed when the coil of the relay controlling it 15 not energised is represented in these diagrams by a black triangle.

The circuits controlling the feed advance of the ribbon being inoperative, the relays H04, H05 and H06 (FIG- URE 8) are not energised, and a capacitor C601 of 600 microfarads employed as a memory device for the control circuits is maintained charged at 48 volts through a normally closed contact CH06 and a resistor R223. The relay H07, which is energised at the same time, maintains the contact CHO7 in the closed position. The contact CHOS of the relay H05 being in the off position, the inductors MRS of the motor for driving the upper roller of the inked ribbon, and the inductor MRI of the motor of the lower roller of the ribbon are energised in parallel with direct current, starting from +48 volts, through the resistor R18 of low value, and the resistor RFll in parallel with the resistor R18, through the contacts CT61-CT62 and CT71-CT72 of the relay (contactors) GT6 and CT7 which are unoperated.

Manual control and feed advance of the ribbon When a printing machine has remained inoperative for some time, for example throughout one night, and in order to ensure uniform printing quality from the outset, it is desirable, with inked ribbons of some qualities, to advance the said ribbon through a distance at least equal to the length which has remained exposed to the air and which may have partly dried during this period of time. The part thus rewound can rapidly return to the degree of moistness of the whole ribbon and thereafter ensure good impression. A similar operation may also be justified simply for tensioning the inked ribbon after it has been positioned.

The spools carrying an inked ribbon having been mounted on the winders of the ribbon mechanism, the push member TR (FIGURES 6 and 7) is depressed for a prolonged period in order to reverse the contact CTR (FIG- URE 7). This operation renders the relays I05 and 104 inoperative if they were in the energised state at that time, by closing of the contact C103 energised by the closing of the lower spool reversing contact CII (FIG- URES 2, 3, 5 and 7). The reversal of this contact results in energisation of the relay H03, which reverses its contact CH03 (FIGURE 8). The relays H04 and H05 are temporarily energised through the reversed contact CH03 and are maintained energised by closing of the contact C1104, the contact CHO7 having already been closed by the energised relay H07. The energisation of the relay H05 reverses the contact CHOS and energises the relay GT6, which rocks the contacts CT61 and CT62, so that the inductor MRS of the upper motor is supplied with single-phase 220-volt alternating current through the contacts connected to the terminals 220 MN (FIGURE 8).

As long as the push button TR remains depressed, the inked ribbon is driven by the motor MRS, while the inductor of the motor MRI continues to be energised with direct current, but only through the resistor RF1. The unidirectional magnetic field produced by this current brakes the rotor of the motor MRI driven by the movement of the ribbon, with a force which is determined by the value of the resistor RFl, whose value is calculated to limit the tension thus applied to the ribbon. In practice, the natural braking of an unenergised motor which is driven through its reduction gear may impart sufficient tension to the ribbon.

When the push button TR for the manual control of the movement of the ribbon is released, the contact CTR returns to its off position, and the relay H03 is no longer energised. The contact CHO3 (FIGURES 7 and 8) falls back and the relay H06, which is then energised through the contacts C1107, CHO4 and CH03, opens its contact CH06. From this instant, H07 is energised only by the discharge of the capacitor C601 through the resistor R223. The useful discharge of the capacitor lasts about 2 seconds, whereafter the relay H07 not being energised the contact 01-107 opens and the relays H04, H05 and H06 are brought into the inoperative position, the contact C1106 falls back and the capacitor C601 is recharged through the resistor R223. The contact CH05 also falls back and, since the relay CT6 is no longer energised, the contacts CT61 and CT62 fall back into the inoperative position and the inductor MRS again receives an intense direct current through the contact CH05 in the inoperative position and the resistor R18. This arrangement has the object of vigorously braking the motors in order to maintain the inked ribbon in the tensioned state and thus to avoid smudging of the printing paper.

Automatic feed advance of the ribbon under normal conditions of use of the machine During normal operation of the machine, the feed advance of the ribbon is maintained substantially continuously by control pulses which, in the example described, emanate from the paper advance control circuits, and are transmitted to the ribbon control circuits through a line FSP (FIGURE 7), at the end of each printing operation, at intervals of time of less than 2 seconds (memory duration of the control device). These pulses, which could also be supplied by printing control circuits, are systemtically applied to a relay L04 (FIGURE 7) which closes a contact CL04, by which a relay L03 is energised and closes a contact CL03, by which the relay H03 is energised, and reverses its contact C1-103 (FIGURES 7 and 8). This triggers a process similar to that produced by the depression of the push button TR, as described in the foregoing. The control pulses transmitted through the line FSP may be of short duration, and therefore a capacitor C connected in parallel with the relay L03 through a resistor R221 prolongs by at least 60 milliseconds the closing time of the contact CL03 through which the relay H03 is energised. During this time, the relay H06, which is normally energised through the contact CH03 in the off position, can no longer be energised and the capacitor C601 of the memory device can be recharged through the contact C1106 in the off position. Thus, as long as control pulses are transmitted to the relay L04 at intervals of time shorter than 2 seconds, the driving of the ribbon is continued.

Monitoring of the feed advance of the ribbon The monitoring of the actual feed advance of the inked ribbon is effected from the contact CAR (FIGURES 2 and 7) which is closed and then opened at regular intervals by the cam 113 disposed (FIGURE 2) at one end of the roller 112 driven by friction in one direction or the other by the inked ribbon itself. The circuits for monitoring the feed advance of the ribbon have the object of verifying whether, in a predetermined time, a ribbon feed advance signal isin fact followed by a feed advance of the ribbon (in one direction or the other). These monitoring circiuts comprise relays denoted by 101 to 107 (FIGURE 7) and a 600-microfarad chemical capacitor C602 which acts as a temperature storage means for the device. In the absence of printing or a control pulse transmitted by the push button TR, the relays 104, I05 and 106 are inoperative. The capacitor C602 is maintained in the charged state through the contact C106 in the 011 position and the resistor R222. The contact C105 in the off position permits energisation of the relay 103 by a control pulse.

A ribbon feed advance control pulse having been transmitted to the relay H03, the relay 103 is also energised through the contacts C105 and C106 in the off position, and it reverses the contact C103. If the contact CAR is open at thi instant, as illustrated in FIGURE 7,

the contact C101 is in the off position, the relay 102 is energised and the contact C102 is in the lowered position. Under these conditions, temporary reversal of the contact C103 energises the relay 104, which is maintained in the energised condition by closing of C104. At the end of the control pulse, C103 falls back and again energises the relays 105 and 106 through the closed contact C104. The contact C105 is reversed and the contact C106 opens. From this instant, the relay 107 is energised only by the discharge of the capaictor C602, through the resistor R222, which can maintain the contact C107 open for two more seconds. Two cases may then arise:

(a) The ribbon advances.1f, after a lapse of time of less than 2 seconds and if, as a result of the movement of the ribbon, the contact CAR closes (or opens if it was closed), then in all cases, the relays I04, I05 and 106 are no longer fed and fall back, owing to the change of position of one of the contacts C101 and C102. The contact C105 returned into the off position will permit a succeeding control pulse to energise the relay 103 as previously described, the contact C106 falls back and recharges the capacitor C602, which has not yet been completely discharged, and the relay 107, which is maintained energised, maintains its contact C107 open.

(b) The ribbon does not advance.1f, as a result of non-closing (or non-opening) of the contact CAR, the relative position of the contacts C101 and C102 does not change, the contact C106 is maintained open and, at the end of the discharge of the capacitor C602 and the relay 107, the contact C107 falls back. The contact C105 being reversed, a succeeding control pulse, and only if there is one, is applied to the relays M08, 107 and 106. The contact C107 closes and the control pulse is applied entirely to the relay M08, which closes a contact CM08 and triggers a system SIA for signalling an advance incident, The relay 106 opens its contact C106 and prevents a ribbon feed advance control pulse from being applied to the relay 103 at the instant when the contact C107 of the relay I07 falls back as a result of the end of the discharge of the capacitor C602.

Reversal of the ribbon movement The inked ribbon is provided, near to its ends (FIG- URE 2), with bars 108 and 109 which are arranged to close respectively an electric contact CIS (FIGURES 2, 3, 5 and 7) which detects the end of the ribbon on the upper spool or a contact CII which detects the end of the ribbon on the lower spool, in order to bring about automatically the reversal of the movement of the ribbon in accordance with the contact which has been actuated. If, for example, the lower contact 011 (FIG- URES 2 and 7) is closed owing to the end of the ribbon on the lower spool, in the course of a series of printing operations, the relay 103 is energised and closes the contact C103 by which the relays J04 and J05 are energized. The relay J04 established by means of its contact C104 a solding circuit at +48 and the relay 105 is energised and reverses the contact C105 (FIGURES 7 and 8), by which, on the one hand, the relay CT6 is no longer energised and returns its contacts CT61 and CT62 into the off position, and stops the motor MRS, which is then braked by the direct current flowing through its inductor, and on the other hand the contact C105 being reversed, the relay CT6 is energised and brings its contacts CT71 and CT72 into the on position for supplying alternating current to the inductor MRI of the lower motor controlling the winding of the ribbon on the lower spool. When the end of the ribbon on the upper spool is thereafter detected by closing of the upper reversing contact CIS, the relay 102 is energised and opens its contact C102, and, since the relays 105 and 104 are no longer energised, their contacts fall back, while, since C105 ha returned into the off position, the relay CT6 is energised and the motor MRS for driving the upper roller again winds the ribbon on to this roller. 1t

may be noted in the example described that at the time of the establishment of the current for starting the printer, the motor MRS for driving the upper roller is always driving, but this has no disadvantage in the operating period because the driving condition of the ribbon due to the action of motors is stored by the control devices as long as the 48-volt direct-current supply is not interrupted. The wear on the ribbon is in fact regularly distributed in successive printing operations without any interruption of the current.

I claim:

11. In a system for moving an inked ribbon in one direction or the opposite direction in a printing mechanism, the combination comprising a first driving roller and a second driving roller, an inked ribbon whose two ends are each secured to a supporting roller on which a portion of the said ribbon is wound, driving means for driving each roller separately in one direction and comprising for each roller an electric induction motor mechanically coupled to the said roller through a reversible speed reduction mechanism, an alternating-current source, a direct-current source, switching means comprising relays for controlling the movements of the ribbon by connecting the inductor of each motor to one of the said two current sources, the inductor of one motor being connected to the alternating-current source, and the armature of the said motor driving the supporting roller to which it is coupled and winding the ribbon on the said roller, while the inductor of the other .motor is connected to the direct-current source and produces in the said motor a unidirectional magnetic field exerting a braking action on the armature of the motor driven by the movement of the ribbon and ensures tensioning of the said ribbon in the printing mechanism.

2. The combination according to claim 1, wherein, for stopping the ribbon in the printing mechanism, the relay switching means are adapted to interrupt the alternating current in the inductor of the motor which drives the ribbon and to pass a strong direct current through the inductors of the two motors so as to brake the armatures of the two motors.

3. The combination according to claim 1, wherein the said switching means comprises a first control relay and a second control relay, each being adapted to be energised or not energised by a direct-current source and each being adapted to actuate a make-and-break contact, two selecting relays each adapted to actuate a make-andbreak contact associated with the inductor winding of one of the said driving motors, in each of the make-andbreak contacts of a selecting relay, the centre blade is connected to one terminal of the associated inductor winding, the make blade is connected to a terminal of the said alternating-current source and the break blade is connected to a common conductor, this conductor being connected through a relatively high resistance to a terminal of the said direct-current source and through a relatively low resistance to the make blade of the first control relay, the centre blade of the latter contact being connected to the said terminal of the direct-current source, while the break blade of the make-and-break contact of the first relay is connected to the centre blade of the second control relay and may be connected through the contacts of the latter relay to one or other of the said two selecting relays.

References Cited by the Examiner UNITED STATES PATENTS 3,145,651 8/1964 Schultz 101-336 3,148,615 9/1964 Irwin et al 101-102 3,185,083 5/1965 Pensavecchia et al. 101-96 3,200,740 8/1965 Schaller et al 10'1-96 3,323,229 2/1966 Anderson 101-336 WILLIAM B. PENN, Primary Examiner. 

1. IN A SYSTEM FOR MOVING AN INKED RIBBON IN ONE DIRECTION OR THE OPPOSITE DIRECTION IN A PRINTING MECHANISM, THE COMBINATION COMPRISING A FIRST DRIVING ROLLER AND A SECOND DRIVING ROLLER, AN INKED RIBBON WHOSE TWO ENDS ARE EACH SECURED TO A SUPPORTING ROLLER ON WHICH A PORTION OF THE SAID RIBBON IS WOUND, DRIVING MEANS FOR DRIVING EACH ROLLER SEPARATELY IN ONE DIRECTION AND COMPRISING FOR EACH ROLLER AND ELECTRIC INDUCTION MOTOR MECHANICALLY COUPLED TO THE SAID ROLLER THROUGH A REVERSIBLE SPEED REDUCTION MECHANISM, AN ALTERNATING-CURRENT SOURCE, A DIRECT-CURRENT SOURCE, SWITCHING MEANS COMPRISING RELAYS FOR CONTROLLING THE MOVEMENTS OF THE RIBBON BY CONNECTING THE INDUCTOR OF EACH MOTOR TO ONE OF THE SAID TWO CURRENT SOURCES, THE INDUCTOR OF ONE MOTOR BEING CONNECTED TO THE ALTERNATING-CURRENT SOURCE, AND THE ARMATURE OF THE SAID MOTOR DRIVING THE SUPPORTING ROLLER TO WHICH IT IS COUPLED AND WINDING THE RIBBON ON THE SAID ROLLER, WHILE THE INDUCTOR OF THE OTHER MOTOR IS CONNECTED TO THE DIRECT-CURRENT SOURCE AND PRODUCES IN THE SAID MOTOR A UNIDIRECTIONAL MAGNETIC FIELD EXERTING A BRAKING ACTION ON THE ARMATURE OF THE MOTOR DRIVEN BY THE MOVEMENT OF THE RIBBON AND ENSURES TENSIONING OF THE SAID RIBBON IN THE PRINTING MECHANISM. 